1. Field of the Invention
The invention disclosed herein relates to a slide out room for a mobile living quarters such as a recreational vehicle. More specifically, the invention relates to a method of shiftability supporting a slide out room.
2. Discussion of Background Art
In mobile living quarters such as recreational vehicles (RV's), it is desirable to be able to expand the usable living space within the RV. This is often accomplished by having one or more slide out rooms in the RV that shift through an opening in the main wall of the RV between a retracted position within the main body of the RV and an extended position protruding out of the main body. In so doing, two major obstacles that need to be addressed are supporting the slide out room in its extended and retracted positions and smoothly shifting the room between its extended and retracted positions.
One general method of supporting the room includes using tensioned cables carried by one of the slide out room or main body, the cables either supporting or supported by pulleys or sheaves carried by the other of the slide out room or main body. Examples of such pulley and cable systems include U.S. Pat. No. 6,254,171 (Young) and U.S. Pat. No. 4,103,462 (Freller). Although both of these disclosures use cables to support the slide out rooms as they shift between their extended and retracted positions, neither relies solely on the tension support of the cables against their sheaves to support the slide out room in both its extended and retracted positions and all its intermediate positions. For example, in Young, the cables are fixedly secured to the main body with anchors, thereby effectively supporting the room with the cables from the anchors. In order to shift the slide out room, the cables must be driven along an infinite loop defined by a set of sheaves. In Freller, the lower pulley rolls along a support track to help support the back end of the room in its retracted position and as it shifts to its extended position. In order to act as both a pulley and a roller, the cable is sandwiched within a groove between the guide rail and pulley.
It would be desirable to have a room that is supported solely by tensioned cables that are wound about a set of sheaves in order to facilitate smooth and easy shifting of the slide out room by a variety of actuation systems independent of the cable and sheave system.